1. Field
Aspects of the present invention generally relate to a Liquid Crystal Display (LCD) device, and more particularly, to an LCD device of which stains of an edge part is improved.
2. Description of the Related Art
Liquid Crystal Display (LCD) devices are used as display devices of laptop computers and portable televisions due to the LCD devices having features of light weight, thinness, and low power consumption. The LCD devices display an image by inserting a liquid crystal substance between an upper substrate on which a common electrode and color filters are formed and a lower substrate on which thin film transistors (TFTS) and pixel electrodes are formed. The LCD devices change an arrangement of liquid crystal molecules with an electric field formed by applying different potentials to the pixel electrode and the common electrode, and adjusting a transmittance of light by using the arrangement change.
Such an LCD device can be classified into a horizontal electric field type LCD device and a vertical electric field type LCD device according to its driving scheme. The horizontal electric field type LCD device adjusts whether light is transmitted by controlling a motion of liquid crystal molecules in a horizontal direction. The vertical electric field type LCD device adjusts whether light is transmitted by controlling a motion of liquid crystal molecules in a vertical direction. From among the LCD devices, Vertical Alignment (VA) mode LCD devices, in which liquid crystal molecules are arranged so that a long axis of each of the liquid crystal molecules is perpendicular to upper and lower display panels, have been widely used due to a high contrast ratio and ease of realization of a wide reference view angle.
Various methods have been proposed to embody a wide view angle in such a VA mode LCD device, one of which is a Patterned VA (PVA) method arranging liquid crystal molecules to be perpendicular to upper and lower substrates and forming an opening pattern in a pixel electrode and a common electrode. In the PVA method, the liquid crystal molecules are divided and aligned by a fringe field, which is an oblique electric field appearing on the opening patterns, when a voltage is applied to the pixel electrode and the common electrode. In this case, the liquid crystal molecules are inclined and rearranged in a radial shape centering from the surroundings of the opening patterns to the outside, thereby transmitting light to display an image.
A mobile PVA (mPVA) mode, which is a kind of PVA method, divides each unit pixel into a plurality of domains and forms a pixel electrode consisting of sub-electrodes corresponding to respective domains. Since a single pixel can be divided into a plurality of domains and an inclined direction of liquid crystal molecules can be determined by adjusting a direction of an electric field, a reference viewing angle can be widened by dispersing the inclined direction of liquid crystal molecules in various directions. When driving an mPVA mode LCD device, there is a problem wherein stains occur on an edge part of the LCD while ion impurities of a sealant forming a seal line of an outside area move to a display area.